Shiplap knife

ABSTRACT

SHEET METAL STRIP IS FORMED INTO A TUBE OF L-SHAED CROSS SECTION, WITH A HANDLE SECURED THERETO. A CHANNELSHAPED PORTION OF THE CROSS SECTION IS SHARPENED AT OPPOSITE EDGES TO PROVIDE A DOUBLE-EDGED, CHANNEL-SHAPED BLADE.   AN ADJUSTABLE LOCATOR IS MOUNTED ON THE TOOL TO FACILITATE ADJUSTMENT OF THE DEPTH OF THE CUT MADE BY THE TOOL.

June 22, 1971 J. E. ONEAL.

SHIPLAI KNIFE Filed Jan. 29, 1969 INVENTOR JOHN E. O'NEAL ATTORNEYS (mm, Wm, WM: 77W

United: S mSP t O ABSTRACT on THE DISCLOSURE Sheet metal stripis formed into a tube of L-shaped cross section, with a handle secured thereto. A channelshaped portion of the cross section is sharpened at opposite edges to provide a double-edged, channel-shaped blade. An adjustable locator is mounted on the tool to facilitate adjustment of the depth of the cut made by the tool.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to tools for working with semi-rigid or rigid boards of compressed fibrous material, and more particularly to a knife constructed for facilitating various types of cuts in such materials.

Description of the prior art In recent years considerable interest has developed in the use of rigidboards made of glass fibers to form heating and ventilating ducts. The forming of such board into useful shapes requires various types of cuts therein. Among these is a shiplap cut useful to form a duct of rectangular configuration by folding the duct at three elongated cuts therein, adjoining the three edges. These edges can also be joined advantageously by providing an appropriate shiplap arrangement. Similarly, duct sections can be connected end-to-end, by appropriate shiplap joints, with tape applied around the exterior thereof,

In order to facilitate the use of such duct materials, it is desirable to be able to fabricate it readily at the job site. This naturally involves the use of tools, and the simpler and more versatile the tools employed are, the easier and better the installation can be. Although knives have been devised particularly for making shiplap cuts, their versatility and convenience in use are limited, and it is an object of the present invention to provide an improved tool for this special purpose.

SUMMARY OF THE INVENTION Described briefly, in a typical embodiment of the present invention, a double-edge, channel-shaped blade is provided with a handle and a locator immediately adjacent the blade, the locator being movable relative to the bridging portion of the channel to facilitate adjustment of dimensions of cut by the tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a typical embodiment of the present invention applied to a piece of duct board to provide a shiplap cut for an end joint.

FIG. 2 is a plan view thereof.

FIG. 3 is an end view thereof.

FIG. 4 is an elevational view as employed for a type of out different from that illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, and as shown in FIG. 1, the blade of the illustrated embodiment is made of a sheet of metal beginning at an edge 11, extending downwardly to the corner 12, extending horizontally to 3,585,720 Patented June 22,, 1971 the corner 13, extending vertically to the corner 14, extending horizontally back to the corner 16, then vertically to the corner 17, horizontally to the corner 18 and down to the edge 19. The overlapping sheet portions 21 and 22 thereby provided are aflixed to a handle 23 by any suitable fastener means such as screws 24, for example. The result is a blade which is of tubular cross section, the tube being in the form of an L, the long legs of the L being 26 and 27, and the short legs being 28 and 21-22.

Referring now to FIG. 2 along with FIG. 1, the edges 29 and 31 of both the upper and lower long legs 27 and 26, respectively, are sharpened back to a vertical lines through the corner 16, and the portion 32 also has its oppositc edges 33 and 34 sharpened. From this it will be apparent that the blade is a double-edged blade of channelshaped cross section with the side walls 26 and 27 and the bridging Wall 32 forming the channel.

In addition to the tubular blade, another feature of the present invention is the locator which, in the illustrated embodiment, includes a planar surface 36 projecting in a plane parallel to the plane of the face 32 of the blade, this being perpendicular to the planes of the faces 27 and 26. This locator surface has projecting marginal surfaces or ears 38 and 39 inclined outwardly and away from the plane of the locator surface. The locator surface is at the edge of the mount portion 41 therefor which can be formed of the same sheet of metal and is provided with a longi tudinally extending slot 42 receiving the stem of a thumb screw 43 which is threadedly received in the portion 44 of the blade. This screw facilitates adjustment of the locator surface toward and away from the plane of the bridging portion 32 of the blade. That adjustment is in the direction of the arrows 4-6 or 47, and maintenance of parallel alignment of locator surface 36 with the plane of wall 32 can be facilitated by piloting the downwardly turned parallel guide walls 45 on the parallel opposite edges of the short legs 11, 21, and 28, and portion 44.

For purposes of example, where this tool is to be used for working with insulation board of the type illustrated in cross section in FIG. 1 at 49, wherein the thickness from the top surface 51 to bottom surface 52 is approximately one inch, the dimension from the corner 14 to the corner 16 of the knife can be one inch. A dimension from the channel wall 32 to the locator surface 36 can be inch with a A-inch adjustment permitted by the longitudinally extending slot 42 in the locator. The width between the edges 29 and 31 can be one and one-eighth inches, for example.

In the use of the tool for cutting the end shiplap for joining two lengths of duct end-to-end, a cut such as shown in FIG. 1 is made. The duct material itself has an outer skin 52 thereon which is usually composed of a woven fabric, a reflective foil, and plastic sheet binder, all joined together as a unit and providing a vapor barrier as well as a neat exterior surface. This skin is secured to the compressed glass fiber body 49. At the abutting end 53, a slot or groove 54 is cut to receive a tongue of the next unit of duct (not shown). In the end of that next unit of duct, a groove is provided to receive the tongue 56 of the unit shown. The overlapping skin 37 meets the skin of the abutting unit at 58 and a tape is applied to seal the joint. The groove is cut by moving the knife from one side edge of the unit of duct to the opposite side edge, i.e. in either direction of arrows 50 (FIG. 2), the position of the locator being adjusted to provide the desired degree of overlap.

Another use of the tool is represented in FIG. 4, wherein there is shown a unit of duct board as it appears looking lengthwise of the duct to be formed therefrom. In other words the duct is formed by folding the duct portion 57 upward, and the portion 58 upward to form side walls,

with the portion 59 to be the bottom wall of the duct and portion 60 to form the top. In orderto facilitate folding ofthe walls it is necessary to cut appropriate grooves such as shown at 61 and 62. For this purpose, the fact that the knife has no obstructions above or below the surfaces 27 and 26, respectively, facilitates location of the end margin 32 thereof atop the skin 63 and Sliding the knife along from one end to the other end of the board to provide the cut for groove 61. The location of the surface 36, by appropriate adjustment, adds a measure of assurance that the blade portion 32 will not sever the vapor barrier provided by the skin 63.

Once the grooves 61 and 62 have been made, and to facilitate the folding up of the walls 57 and 8, an additional lengthwise cut needs to be made adjacent each groove. This is illustrated, for example, by the dotted line 64-66. This will receive the portion 67 of the wall 58 when it is folded upwardly in the direction of the arrow 69 to provide the vertical wall. It will be readily recognized that by inverting the tool from its attitude shown in FIG. 1, and by making the appropriate adjustment of the locator surface 36, the tool can be run lengthwise along the edge 71 of the board while the wall 58 is hanging down as shown by the dotted outline 58a to cut away the segment 73 of rectangular cross section. Once this has been removed, the portion 58 can be swung upwardly from the position shown at the dotted outline 58a in the direction of arrow 69, and placed vertically, with portion 67 thereof being received where the block 73 had previously been located.

So it is seen that by making the locator versatile as it is, and having it the exclusive item in the upwardly projected area of surface 27 above the surface 27, and by avoiding appendages below surface 26, this knife is capable of providing not only the shiplap construction at ends of adjoining units of duct work, but is also capable of providing a shiplap-type of construction along the corners of the lengths of units of the duct, to provide a sturdy duct unit. Accordingly, this knife has the type of versatility making it extremely effective in the on-site preparation and installation of duct of this type.

The invention claimed is:

1. A shiplap tool comprising:

a blade having an L-shaped tubular cross section,

. tionthereof, :1 a. a

the L of said blade havinglong legs and short legs,

and a locator mounted to said blade, said locator being movable between positions nearer to and farther from the end of the long legs of said L.

2. The tool of claim 1 wherein: I v

- said locator is disposed perpendicular to thelong legs 'of said L, said locator having leading and trailing margins inclinedwith respect to the portion between said margins. i

3. The tool of claim 2 wherein:

opposite edges of the long legs of said L are sharpened.

4. The tool of claim 1 wherein: I

the long legs of the L are planar, and

'said locator is the exclusive item disposed in the space defined by a projection of the area of a'shorter one of said long legs perpendicular tothe plane of said shorter one.

5. The tool of claim 4 wherein? I said L has an elongated planar portion bridging the long legs of said L, said locator having a planar locator surface parallel to said bridging portion and guide walls piloting on the short legs of said L and extending perpendicular to sad locator surface to guide movement of said locator toward and away from the plane of said bridging portion.

a handle connected to said blade to facilitate utiliza- References Cited UNITED STATES PATENTS ROBERT C. RIORDAN, Primary Examiner J. C. PETERS, Assistant Examiner US. Cl. XR. 3 0-283 

